
.button{
    display: inline-block;
    border-radius: 5px;
    border:none;
    box-shadow: black 0px 0px 3px;
    padding: 10px 10px;
    text-align: center;
    transition: all 0.5s;
    vertical-align: middle;
    cursor:pointer;
    margin: 10px;
}
.button:hover{
    box-shadow: black 0px 0px 10px;
}

#navBar{
    position: absolute;
    z-index: 1;
    left:0px;
    top:0px;
    height: 70px;
    width:650px;
    margin: 0%;
    padding: 0px;
    background-color:darkslateblue;
}

#subjectNet,.defContent{
    display:none;
    position: absolute;

    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    margin: auto;
}

#subjectNet{
    width: 100%;
    height: 100%;
}

.defContent{
    width: 50%;
    height: 70%;
    border-radius: 10px;
    box-shadow: 0px 0px 10px rgb(255,255,255);
    background-color:rgba(0,128,255,0.5);
    position: absolute;
    color: yellow;
    font-size: 24px;

    animation-name: showFromUp;
    animation-duration: 0.6s;
    animation-fill-mode: both;
    animation-play-state: paused;
    animation-timing-function: ease-in-out;
}



.defContent header{
    color: yellow;
    font-size: 36px;
    text-align: center;
}
.defContent p{
    color: white;
    font-size: 20px;
    margin: auto 40px;
    word-wrap: break-word;
}
.defContent a{
    color: greenyellow;
    font-size: 20px;
    word-wrap: break-word;
}
#bookPage{
    display: none;
    position: fixed;
    z-index: 3;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    
    overflow: auto; 
    background-color: rgba(0,0,0,0.3);
}

#bookBackground{
    background-image: url(../resource/book.png);
    background-size: cover;
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
    height: 600px;
    width:  480px;
    
    margin: auto;
    background-color: rgba(0,0,0,0.3);
}
#bookContent{
    position: absolute;
    margin: auto;
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
    height: 500px;
    width: 400px;
    overflow: auto;
    
    
}
#bookContent header{
    text-align: center;
    font-size: 36px;
    font-weight: bold;
}
#bookContent p,a{
    text-align: center;
    font-size: 24px;
    font-weight: normal;
    word-wrap: break-word;
}